UNIX 32-bit Maximum Date is "20380118"PHP_INT_SIZE = 4 Bytes (32 bits); PHP_INT_MAX (Maximum Integer) is 2147483647It is hoped that most PHP installations will be at least 64-bit well before 2035.In the meantime, this uses a kluge to align the days of week, correctly, up to 2100/02/28

TOO MANY DAYS IN MONTH (02/29) (GS_Date_Range): 20190229o3: GS_Date_Range ("20190229", "20190323")
yields: "2019 March 29 to March 23"o4: GS_Date_Range ("20200229", "20200323")
yields: "February 29 to March 23"(… but 02/29 is OK for Leap Year)